1. Field of the Invention
This invention relates generally to alarm systems and more particularly to an intrusion alarm and detection system which monitors a predetermined space, initiates an alarm as a result of an intrusion into the predetermined space and records the occurrence of the intrusion. The system includes a reliable and substantially foolproof means by which to remotely arm, disarm and test for the occurrance of the intrusion without causing a false test report because a user inadvertently arms a disarmed system or disarms an armed system.
2. Description of Related Art
Burglar alarm systems which detect unauthorized entries into protected premises such as houses or apartments and produce audible or visual alarm signals as a result of such entries are well known. Automobile and personal property alarms which are remotely armed, disarmed and tested are also known in the art.
Typical house protection systems produce an audible or visual alert to warn occupants that an intrusion is occurring. If occupants are not at home, the alarm may or may not notify neighbors or police of a break-in. House alarm systems usually stop signalling after a predetermined period of time and, should no one respond to the alarm, occupants reenter their premises unaware of the possibility of confronting a remaining intruder.
For apartment buildings and other types of multiple occupancy dwellings, sonic burglar alarms are normally limited by local regulations to relatively short alarm time periods to avoid the nuisance of false alarms in densely populated premises. In small one or two room apartments, an intruder can easily find a concealed alarm in the process of producing an alert and quickly disable it. Neighbors may not hear the alarm and, even if they do, may not bother to inform the returning occupant of the break-in. The returning occupant enters his or her apartment not knowing that an intruder may be in their premises.
Remotely controlled automobile alarm systems are generally connected to a car's electrical system and utilize its horn and head lamps as alarm signals to discourage theft. Generally, a returning car owner is not as concerned about a remaining intruder as, for example, a returning apartment occupant since an intruder in an automobile can be observed by the owner before the owner reenters the vehicle whereas an intruder may remain unseen in an apartment.
The following United States Patents show prior art alarm systems of the type to which the present invention is applicable:
U.S. Pat. No. 4,794,368, which issued to Edward Grossheim and Michael Nykerk on Dec. 27, 1988 teaches an alarm system having three RF channels and a hand-held remote controller with three button switches. Pressing any one of the three buttons once or pressing any combination of the three buttons simultaneously controls up to seven distinct functions. Grossheim's disclosure does not address the problem of the user misusing the remote controller, thus, creating a false test response. False reports in systems such as Grossheim's may occur as a result of either the user pressing the wrong button or wrong combination of buttons or buttons being accidentally depressed. A false status report is a significant problem affecting the safety of the user particularly if the surveiled space is not visible to a returning occupant.
U.S. Pat. No. 4,897,630, a continuation-in-part of U.S. Pat. No. 4,794,368, which issued to Michael Nykerk on Jan. 30, 1990 discloses a computerized alarm system for detecting, signalling and reporting the occurrence of a penetration toward or an unauthorized entry into a defined area, such as an automobile. It also discloses a self-contained monitor intended to protect a variety of objects such as a boat, a trailer, a house, etc. and which communicates with a remote controller in a similar manner as taught in U.S. Pat. No. 4,794,368. Nykerk discloses a four button, four channel system wherein pressing any button once or pressing any combination of the buttons controls up to sixteen separate functions. A system which relies on selecting one of several buttons and pressing it once, or selecting a specific combination of buttons and pressing them simultaneously, to prompt a specific system response is expensive to manufacture and difficult to use particularly if the returning occupant has to operate the remote controller in a dimly lit or dark environment. Further, Nykerk discloses a system wherein an intruder is frightened away by a series of synthesized voice alarms but does not address the problem of an intruder remaining undetected in the surveiled space because the remote controller was misused thereby producing an incorrect test response.
As can be seen from the prior art, alarm systems for protecting automobiles, houses and apartments are complex, expensive and depend on various alarm schemes to frighten away would-be intruders. Existing systems do not specifically address the problems associated with self-contained intrusion detection monitors which are disposed to monitor spaces which cannot be seen by the system operator. In such applications, existing remotely controlled systems do not solve the problem of a returning occupant inadvertently either pressing the wrong button or combination of buttons and erasing the record of an intrusion or pressing the wrong button or combination of buttons and arming a disarmed system thereby causing a false report resulting in an encounter with an intruder.
It is apparent that there is a need for a cost-effective remotely controlled system which includes a minimum number of commercially available components, which consumes a minimum amount of electrical power and which can be integrated in a compact housing for convenient placement in an area to be surveiled. In addition, a system is needed that may be purchased and installed, for example, by an average apartment dweller, which is remotely controlled by a method that is easy to use, and substantially foolproof and which operates in a manner such that a returning occupant has a reliable method by which to test for a remaining intruder.